Oil slicks that together are twice as large as France polluted the sea from 2014 to 2019, which equates to more than 1.5 million square kilometers of oily pollution in the ocean. And almost all of this considerable dirt has our signature: more than 94% of the oil detected comes from human activities, according to research published this Thursday (16), in the journal Science.
Estimates for the human origin of oil are considerably larger and more comprehensive than those of other surveys conducted to date.
American and Chinese researchers at Nanjing, South Florida and Florida State Universities used more than 563,000 satellite images to detect about 452,000 oil slick locations in seas from all regions of the world.
In addition to points with natural leaks (the escape of the substance from natural reservoirs on the seabed can happen, but only about 6% of the area detected with oil had this origin), the analysis found frequent leaks and discharges of oil from exploration infrastructures. of oil and gas at sea.
The global map of pollution constructed by the scientists shows that the leaks or releases are concentrated mainly on the coasts. About 50% of the spots occurred at a distance of 38 km from the coast, with their peak at about 7 km.
The most critical regions, according to the researchers, are the seas of Java (near Indonesia) and southern China, as well as the Gulf of Guinea (in Africa).
In some places, scientists say they have observed alarming frequencies of leaks, which could mean a lack of marine environmental enforcement — which could easily be resolved with satellite monitoring.
Marine oil contamination goes beyond spills on platforms and natural sources. Dirt can also originate on land — and end up at sea — and in the disposal or escape of oil from ships.
Through satellite images, scientists were able to identify places with a high number of spots that coincide with shipping routes, in addition to more than 82,000 linear spots that were probably related to ship escapes.
Approximately 20% of marine oil pollution originates from maritime transport, according to the research.
And it is in the midst of these “other sources” of pollution (leaks on land and from ships) that Brazil is mentioned in the work published in Science. Research data indicate that all the spots identified in the country during the study period were within this group of “other origins”, that is, they had no relation to platforms, pipes or natural sources.
It is worth remembering that the period of time in which data were collected through satellite images coincides with the environmental catastrophe of oil slicks that spread along the Brazilian coast, especially in the Northeast.
More than a thousand places in 11 Brazilian states were affected by the oil that originated, according to the PF (Federal Police), on the Greek-flagged vessel Bouboulina. The PF investigation points out that the company Delta Tankers, commander Konstantinos Panagiotakopoulos and chief engineer Pavlo Slyvka did not notify the authorities of the disposal of the material in the ocean. All of them were indicted.
Brazilian investigations took a long time to find a person responsible. The conclusion of the PF came only at the end of last year.
In part, this can be explained by something that became evident as the stains reached Brazilian beaches: it is not necessarily simple to detect oil spills using satellite images and associate them with an origin. The spots can move under the surface (something that was witnessed in the Brazilian case) and the trajectory can be affected by winds and tides, as the authors of the study in Science point out.
But, in addition to the historic leak in Brazil in 2019, other stains still reach Brazilian beaches. This year, beaches in Ceará have already been hit by oil. In at least one of the cases, after analyzing the material, it was pointed out that the origin was not the Greek ship responsible for the 2019 problem.
The research also points out that oil contamination is considerable on the coasts of emerging countries, such as China, Vietnam, Indonesia, Malaysia and Brazil.
The release of oil into the ocean is a relevant problem, which can affect marine life —one of the concerns in Brazil was the possible impact on the corals of the Abrolhos National Marine Park, which has a unique biodiversity—, leading to a loss of diversity and contamination. of food chairs.
Referring to pollution by maritime transport, as occurred in Brazil, the researchers affirm that, despite the existence of an international convention that deals with pollution by maritime vessels, the substantial contribution of oil disposal by ships shows an urgent need for greater regulation and international cooperation in the sector.
